Do you know the many surprising
connections between the deepest parts of
space and the deepest recesses of our
ocean?
Both are cold, dark places where humans
cannot breathe and where the pressure
alone is enough to kill you. Both upset
our normal experiences of gravity,
providing explorers with a strange
weightlessness or buoyancy if they could
somehow survive being there in the first
place. And both contain many unsolved,
captivating mysteries. Our oceans are
filled with life we've never seen
before. And who can say what lurks in
the unexplored corners of space?
I was initially caught off guard when I
heard that NASA had turned its attention
towards exploring the hallel zones deep
in the ocean. After all, NASA is
normally about space. What are they
doing deep under the water? and on
Earth.
I'm Alex Mccoan and you're watching
Astramm. Put on your diving gear and
join me in a world of undersea
facilities, uncanny life, and an
environment so hostile, we've mapped
more of Mars than of this terrain on our
own planet.
In 1957, a year before NASA was founded,
a paper published by the Journal of the
Royal Society of Arts claimed the deep
oceans covered over 2/3 of the surface
of the world. And yet, more is known
about the shape and surface of the moon
than is known about that of the bottom
of the ocean.
This was a reference to the fact that in
the world before echo sounding
technology was commonly used to map the
seafloor, we didn't know much about the
topography of what was down there. We've
come a long way since then. But while we
have mapped the moon thanks to
satellites and telescopes, we have still
only mapped 23.4%
of the ocean floor in high resolution.
In fairness, this still represents an
area of 120 million km, about three
times the moon's surface area. So, the
old saying no longer holds entirely
true. Hence why we can instead talk of
Mars, which has a surface area of 145
million km. But still, it's a profound
gap in our knowledge of our own world.
NASA was founded in 1958 with the
purpose of expanding human knowledge of
phenomena in the atmosphere and in outer
space and developing vehicles and
technologies that would help them to do
so. Exploring the ocean was not
originally on their radar or sonar.
However, in 1978, NASA began monitoring
the ocean with their first dedicated
oceanographic satellite, SESAT, which
was capable of collecting data on sea
surface winds, surface temperatures,
wave heights, and other features. This
helped them learn more about our
planet's oceans and their impact on the
global climate. Still, some of NASA's
most exciting foray into the ocean only
began at the turn of the millennium.
One way in which the sea can prepare
astronauts for space is through
simulated space experiences.
About 8.7 km off Kilago in Florida is
the world's only undersea research
laboratory, Aquarius Reef Base. Built in
1986, it is a small three- roommed
habitat large enough to house six people
at a push with a main room that combines
sleeping and living quarters, an entry
dock, and a wear porch for entering the
sea around it. It was originally
designed to help aquinauts remain at the
bottom of the sea for weeks at a time
through a technique known as saturation
diving. By remaining at the depth of 19
m, the human body becomes saturated with
gas dissolved in its bloodstream, which
allows these researchers to stay at
depth without ill effects for much
longer periods of time, 9 hours for one
dive rather than 1 or 2 hours. This made
it ideal for biologists wanting to study
the local environment in situ. In 2001,
however, NASA along with other space
agencies such as realized that it made a
great space training location. The
cramped living conditions mimic those
found on the International Space
Station, so astronauts who spent a week
at Aquarius Reef Base would get a vital
taster of what life would be like up
there.
It also allowed them to practice
performing experiments and generally get
used to the expected and unexpected
aspects of life in a hostile
environment. NASA began the NEMO program
or the NASA extreme environment mission
operations and that same year began
sending their astronauts to the habitat.
There have been 23 Nemo missions since
then, merging astronaut crews from a
variety of different space agencies
which lasted up to 3 weeks. Astronauts
there became aquinauts and got the
chance to dawn deep space suits, getting
a taste for what space walks might be
like outside of our planet, readying
them for the day humans return to the
moon or go to Mars. This was not the
only use NASA had for the ocean,
however. Perhaps the most significant
training was not for NASA's astronauts,
but rather for the machines that would
one day visit the largest oceans outside
of planet Earth.
Let's now go deeper and consider the
exploration of alien oceans.
Our solar system is home to many large
oceans outside of Earth. Jupiter's moon
Europa and Saturn's moon Enceladus, to
name just two, have significant bodies
of water beneath their kilometer thick
icy surfaces. In spite of only being 1/4
of the Earth's diameter, scientists
believe that Europa holds twice as much
water as all of our oceans combined.
This is an intriguing concept as even
though no sunlight penetrates down to
those steps, the mixture of liquid water
bordering a rocky inner crust would make
both of these locations ideal candidates
for life.
Scientists have considered how to best
test to see if life really has arisen in
the oceans of icy moons. In 2024, NASA
will launch the Europa Clipper with the
mission to fly by the moon Europa and
scan it to learn more about the depth of
its icy shell to try to determine the
composition of its oceans and generally
get a better picture of the moon as a
whole. However, Europa Clipper will only
be laying the groundwork for future
missions, which one day might see
cryobots melting through the 10 km thick
icy shell of Europa using nuclearpowered
radiators to penetrate its oceans and
see firsthand what lies below. Once down
there, no radio signal will be able to
reach them easily. Messages will be
relayed via a vast cable brought down
through the ice along with a cryobot.
This means that such cryobots will need
to be able to autonomously descend a
further 100 to 200 km to explore the
dark, chilling, and highly pressurized
environment they're likely to find to
see what alien life might swim in those
waters. So, with a mission objective on
the horizon to explore deep, dark waters
in search of neverbeforeseen life, what
better place to start than the
unexplored oceans we already have at
home? The deepest parts of the oceans on
Earth are only 11 km deep. But due to
the gravitational differences between
Europa and Earth, the pressure you'd
experience between the two are much more
comparable than you might think.
Europa's 100 km deep ocean is thought to
have a hydrostatic pressure between 130
to 260 megapascals,
which if it existed in an ocean on Earth
would equate to a depth of around 13 to
26 km. This is much better than if you'd
had to go hundreds of kilome down on
Earth, but it's still no picnic.
Pressure at the bottom of the Mariana
Trench, the deepest place in our ocean,
is 1,100
times the pressure on the surface, which
is enough to crush the individual cells
in the human body or to implode most
submarines.
And yet, life survives there. And it
doesn't just survive, it thrives.
The deep sea explorers of the Galapagus
hydrothermal expedition in 1977 using a
specially reinforced remotely operated
vehicle that could survive those
pressures were shocked to discover not a
barren wasteland but thriving ecosystems
gathered around hydrothermal vents on
the ocean floor down there. Tubeworms,
crabs, and fish were found in rich
abundance. As scientists performed more
dives, they found all manner of strange
life forms down there. Shrimp like
amphipods the size of your hand. Giant
ethereal big fin squid. Squid that were
8 m long and looked positively alien. In
the depths between 6,000 and 11,000 m,
in an area known as the Hadel zone,
named after the god of the underworld,
Hades, life had learned to adapt to
conditions in ways no one could have
imagined possible. And this incredible
adaptability gives scientists a better
understanding of what might be possible
on other worlds.
The deepest parts of the ocean are
mostly found near the fault lines of
continental plates, where one plate
subducts under another. These deep
trenches create a unique V-shaped
environment that channels organic debris
from above down into a sludgy pool.
Whenever a carcass falls down there, the
organisms in the Hadel zone are somehow
able to quickly detect it and arrive
within minutes. Other organisms rely on
nutrient-rich liquids pumped out of
thermal vents. If you added up all these
trenches into one land mass, you would
end up with an area the size of
Australia, a whole unexplored continent.
NASA wants to explore these regions
using autonomous drones, perhaps whole
swarms of them that would be able to
detect locations of interest such as
thermal vents and would be able to map
out the terrain using cameras and
onboard AI similar to that used by the
Perseverance rover on Mars. It's a
challenging task. Not only would such a
drone need to be able to withstand the
excessive pressure, but the temperature
around such thermal vents can spike to
hundreds of degrees. Drones would need
to be able to survive rapid temperature
swings if they are able to survive. In
2014, one such deep sea drone known as
Narius was sent into the Kerdc Trench
off the coast of New Zealand. This is
the area NASA has selected as testing
ground for its new equipment. However,
sadly, Narius was not able to survive
the pressure down there in spite of
having succeeded on Hadel dives before
and it imploded. Pieces of plastic were
later found floating to the surface.
NASA's latest drone is Narius's
descendant, a smaller, lighter,
autonomous submarine known as Orpheus.
Orpheus has yet to enter the depths of
the Hadel zone. Instead, it is being put
through its paces in shallower waters.
But if it works, its lighter design
would make it easier to transport on a
rocket to the oceans of Europa at some
point in the distant future.
Although this dream might not be so
distant after all. In 2023, NASA's
Planetary Exploration Science Technology
Office gathered a team of 40 top
researchers from multiple fields in the
California Institute of Technology to
discuss how close we might be to making
this trip. A surprising amount of
technology needed is already there.
Their conclusion was that the mission
was feasible, scientifically compelling,
and the most plausible near-term way to
directly search for alien life in situ
on an ocean world. With the combined
information being gathered by Europa
Clipper and the technical
experimentation being done with Orpheus
and other autonomous submarines like it,
perhaps it is something we will see
within our lifetimes, although no
concrete plans have been made yet. When
it finally does happen though, and a
human-made drone starts to swim in those
dark seas across the Gulf of space, what
will it see? Perhaps it will feel
strangely like home. We are waterbased
life forms here on Earth. The first
large complex animals formed in our
oceans. All life is dependent on water
to live. Rather than arid, rocky, and
dusty wildernesses, there will be
something strangely soothing about
exploring oceans beyond our own, like
entering a place we already know, even
though we've never been there before.
Does something lurk in those alien seas?
Although it's only speculation, the
sheer fact that this might be true is
enough. To discover that life came to
exist not once but twice in just our own
solar system would have massive
implications on life's prevalence in the
universe as a whole. It would mean life
is likely abundant and we ought to be
ready to see a lot more of it out there.
But proving it is the challenge. Only by
perfecting the technology here on Earth
will we be able to crack open those
frozen shells, enter those inky depths,
and find the definitive answers we seek.
For NASA, their mission to find life in
our solar system begins in our oceans.
[Music]
Take a walk with me through an ancient
verdant land. So vivid are the colors
and aroma of the entangled fauna that it
takes you an age to notice something
isn't as it should be. It's all quiet.
The near absence of birds and mammals is
the only indication that this land is
dying. Its fate sealed by the ending of
an ice age. Waters are rising. The lush
landscape below your feet will soon be
30 m below the surface of the Pacific.
Any species able to migrate have escaped
to continue their fight for survival in
a warming, shrinking world. Those given
life by their roots are held to perish
by them.
What is happening here? What can we
learn from the history recorded deep in
the melting polar ice is of vital
importance? Because right now it's
happening again. What is causing the ice
caps to melt in the present? How will it
affect the most powerful climate systems
on Earth? And what hidden dangers does
the ice contain? I'm Alex Mccoan and
you're watching Astramm. Join me today
as we look at what makes ice such an
interesting and crucial feature of our
planet and imagine a future wetter
Earth. One whose existence may have
already been forged.
On Astramm, we love to explore gigantic
objects in our universe whose scale
through time and space stretch almost
beyond our grasp. Look up towards
Cassiopia and there is our closest
galaxy, Andromeda,
2.5 million lighty years away, 200,000
lightyear from edge to edge. Yet,
despite its magnitude, we can connect to
it. So, it's curious to me that looking
only 80 years to our future feels too
distant to connect with to understand
that things we do today affect
tomorrow's world. So, let me take you
there. At the beginning of our journey
is the ice. Ice is a remarkable
substance, one that can store vast
amounts of energy. As a comparison,
energy stored in modern electric cars
capable of accelerating tons of metal to
over 160 km/h and carry both it and you
hundreds of km could scarcely melt ice
that would fit on its back seats.
The energy storage capacity of ice is a
large part of the reason that the
climate has been so stable for the past
12,000 years. The ice is acting as a
buffer against extreme temperature rises
and falls. The holene has been a unique
period in Earth's history for another
reason too. The rise of human
civilizations made possible through the
development of agriculture.
The Antarctic ice cap first formed
around 37 million years ago. The Arctic
2.7 million as old as the light reaching
us from Andromeda. And both caps are
important for our stable climate to this
day. Their historical size has largely
been defined by Earth's position and
tilt in the solar system. Movements that
affect the amount of energy that our
planet receives. These movements are
known as Melankovich cycles, which I've
covered in a previous video. According
to these cycles, the ice at the poles
should be increasing. We should be
heading into an ice age. The sea levels
should be falling as the ice caps get
deeper, but instead the polar ice is
melting. Massive amounts of energy are
being absorbed by the caps. And not only
are we going in the opposite direction
that the Malankovich cycles predict, the
ice loss is accelerating.
Should all the ice melt, we are facing a
70 m sea level rise, which will flood
all coastal cities on the planet.
Fortunately, that degree of ice loss is
exceptionally unlikely. But we do need
to know how much sea level rise to
expect so that we can plan ahead and
protect Earth's ecosystems.
To predict just how much, we need to
understand why and how the ice is
melting.
We know the release of greenhouse gases
is a driver of today's global warming,
overpowering the melangage cycles,
causing the ice caps to melt and the sea
level to rise. But I was astonished to
find out that this hasn't always been
the case. Detailed records kept in the
Antarctic ice core reveal that in the
past it was increasing temperatures that
caused increasing CO2 levels. Cause and
effect were flipped. But isn't that a
blatant contradiction? Well, actually,
no. Each positively influences the
other. It's just a case of which happens
first. We see this play out as the
increased temperatures of today's
climate thaw the perafrost around the
Arctic Circle, releasing long stored
carbon reserves, which in turn
accelerate further global warming.
The mechanism by which increased CO2 and
temperature affect the polar regions
reveals a complicated and fascinating
climate system. Greenhouse gases trap
infrared heat radiation emitted by the
surface of the Earth. This heat is
retained by the atmosphere and the
ocean. Around 90% of the energy
increased is absorbed by the ocean,
which is no surprise given it has almost
250 times the atmosphere's mass.
So, where does this extra energy go?
Well, as anyone who's touched a hot
stove or licked a ski lift chair knows,
heat moves from hot things to cold
things. So, it makes sense that it is at
the cold poles where we see many times
the average global temperature increase
because that's where the temperature
gradient demands that the energy flows.
and it's flowing there primarily through
the ocean currents. Because of its
density and heat capacity, water is very
effective at transferring energy. That's
why water is used both as a coolant in
cars and a heating medium in homes and
why air with a low density and low heat
capacity is often used as an insulator.
That difference allows you to sit
comfortably in a 90° C sauna for many
minutes while you'd reflexively be
unable to insert past your fingertip
into water of the same temperature.
Other factors play a role in melting the
ice too, like the albido or whiteness of
the ice.
Soot darkens the surface of the ice,
causing it to absorb more energy from
the sun. Air quality measures are
reducing particullet in the atmosphere
and on the ice, meaning we will see less
melt from ice directly absorbing the
sun's energy. But the lowering of
particullet in the atmosphere also
blocks less sunlight overall. So more
energy reaches the surface accelerating
the greenhouse effect. I told you it's
complicated.
Let's explore the ways the oceans are
melting the polar ice as it is happening
right now on the West Antarctic ice
shelf, a particularly vulnerable area.
It contains ice in several forms.
Sea ice is very seasonal and is
responsible for the doubling of
Antarctica's area through winter. This
ice melts through contact with the ocean
as ice cubes do in a cocktail. The
direct impact of all the sea ice melting
would only contribute a few centimeters
to sea level rise, but its importance
lies in its role as a barrier to the
otherwise exposed ice shelf.
The sea ice insulates the oceans from
atmospheric warming and keeps the
humidity and temperature of the air
above it low, being fresh and white like
the most fairy tale of glistening winter
flurries. It also reflects a large
portion of sunlight back into space.
When this sea ice is low, it exposes the
ice shelf which protrudes almost all the
way around the Antarctic. These floating
ice shelves can be gigantic.
Some like the Rosson Ronnila shelves are
greater in area than my home country,
the United Kingdom. The warm sea water
eats at the underside of the shelves.
Huge icebergs the size of our biggest
cities can break away as it weakens and
drift as far as Africa. Since these ice
shelves are melting, they also
contribute minimally to the rising sea
levels. But it's what the ice shelves
hold back that has the most potential
for sea level rise. As the shelves
shrink, the main body of sheet ice that
sits at top land is more exposed,
allowing faster flow rates from glaciers
and ice streams. But don't be fooled.
These ice streams are far bigger than
their name would suggest. Incredibly,
some are as wide as the mouth of the
Amazon, hundreds of kilome long and
kilome deep, all flowing towards the
sea. Feeding these streams is the
colossal ice sheet itself.
Since the ice sheet is supported on
land, the mass of ice melt leads to a
direct increase in sea level.
These ice melting processes are natural
phenomena and would still occur without
global warming. The poles take fresh
snowfall and ice formation every year,
which adds to the mass of the ice. And
just for them to retain at their current
size, we would witness sea ice melting,
ice shelf carving, and glacial flow.
Although at this very moment, Earth's
polar ice sheets are far from
equilibrium. The rate at which they are
losing ice is quicker than fresh snow
can fall, meaning that they are
shrinking. Because of the extra energy
in our oceans and in the atmosphere
captured by greenhouse gases, we are
already committed to significant ice
sheet loss. Can we say how much sea
levels will rise from the melting alone?
If you thought it would be a simple case
of calculating the volume of ice lost
and adding it to the volume of water in
the seas, well, you can join me in being
wrong. To arrive at an accurate
estimate, we need to understand a few
other interactions.
We tend to think of Earth's crust as
solid, but given enough force, the Earth
will change shape, too. As the ice
melts, the continental plate that
supports it bears less weight and rises
up above sea levels. While at the
equator, the coastal land shrinks into
the sea, creating localized sea level
falls and rises. But the single biggest
addition to sea level rise to date
required no additional water and was
simply due to the thermal expansion of
what was already there. Around half of
the sea level rise we have already seen
since the industrial revolution has been
due to this expansion.
This process is easy to calculate and we
know how it will contribute to sea level
rise in the future. However, the deluge
of cold, fresh water being dumped into
the salty sea has other less predictable
consequences.
Remember, Earth's systems are
dynamically intertwined. A feature of
these dynamic systems is that they are
vulnerable to dramatic changes in
behavior known as tipping points. As
with playing Jenga, the tower becomes
less and less stable as we mine the
lower levels for material to build even
higher. Eventually, merely touching the
next brick brings it crashing down. This
would cause a very rapid phase change.
One tipping point that could occur
within our lifetime is the slowing of
the Atlantic meridian overturning
circulation.
This is an oceanic flow, a powerful
energy transfer system. Should it weaken
or collapse completely, sea levels on
the eastern seabboard of America could
rise by up to 1 meter. But in Europe,
coastal waters would recede. However,
Europe would face other more extreme
consequences.
Around the world, rainfall patterns
would change drastically, pushing some
ecosystems to become rainforests while
pushing others towards desertification.
To understand how all of that is
possible, let's look at how the AMC
functions. Now, the AMOC is part of the
thermo halaline circulation system. It
is driven by changes in heat, thermo and
salt concentration, haline. The AMOC
brings warm tropical waters up past the
United States and across to Europe,
helping to make northern Europe warmer
than it ought to be considering its
proximity to the polar circle. As these
waters continue north to the Arctic, it
is partially frozen into sea ice, which
leaves cooler, saltier water to sink to
the bottom of the ocean, where it then
flows back south to complete the cycle.
However, the melting of the Greenland
ice sheet is inundating the northern
part of the AMOC with fresh water,
diluting the seawater, making it less
salty and less dense. This makes the
gradient directing the water to sink to
become shallower, slowing down this part
of the cycle and reducing flow. Just as
a slow middle lane driver on the
motorway can cause a tailback stretching
frustratingly far back across all lanes.
The slowing down of the AMO backs up
water on the American east coast and
reduces the flow to Europe, meaning that
sea levels would rise in America while
Europe would be spared. Though that's
little consolation to a continent that
will lose much of its way of life and
food production capacity through cooler
temperatures. The UK alone is facing an
average temperature drop of 10° C, which
would make it colder than Iceland. Now,
the melting Greenland ice sheet also
contains organisms that we haven't seen
on Earth in hundreds of thousands of
years. When a new predator travels to an
ecosystem not evolved to live with it,
it can upset its delicate balance. This
is also true of a pathogen traveling
through time. Most of the species will
be harmless, but as we saw in 2020, it
only takes one black swan to change
everything. With more cells being
released from ice melt each year than
there are grains of sand on Earth, the
risk one is a black swan is significant.
A risk that increases with a depth with
the perafrost Thor. The further back in
time a potential pathogen is from, the
bigger the jump in its genome and the
lower our ecosystems readiness for it.
So, the world is changing.
As we have seen, ice is an incredible
recorder of Earth's history. Through
studying its secrets, we can see Earth's
past. Just as the ice cores detail
Earth's ecosystem as the bearing
straight flooded, it contains our
history, too. As the ice melts, it
reply's
environmental missteps by re-releasing
trapped chemicals we have produced.
CFC's stored in the ice can again
deplete the ozone and accelerate Arctic
ice loss. Chlorinated pesticides, many
long banned from use, can find their way
back into Earth's ecosystem, some of
which will have been made even more
potent by their time stored in ice.
Vaporized lead from the use of leaded
petrol will also be re-released as the
ice layers that contain it melt away.
This chemical cocktail adds yet more
stress to a global ecosystem moving ever
closer to an invisible edge. When we add
all these factors together, the year 20,
100 could look very different. Exactly
how different is under our control. The
current predicted average sea level rise
is 0.5 m. That doesn't sound like much,
does it? A map of the world's coastlines
would look almost unchanged.
However, it's not the averages, but the
black swan events. The storms, the
floods, the heat waves that drive human
behavior. By the year 2100, a population
the size of the US will be exposed to
regular coastal floods. Faced with
increased risk, where will Earth's
coastal populations move to? How much
will our way of life change?
The rich diversity we see in cultures
and species on Earth is born out of
adapting to the environment. Both
humanity and life itself have
demonstrated time and time again that
they are irreressibly adaptive. Humanity
can and has to learn from its past and
look to the future. So there is hope.
While the melting ice reminds us of the
environmental damage we have been
responsible for since the industrial
revolution, it also reminds us of how
often we came together to make a change
for the better when we understood how we
were affecting our planet and ourselves.
I believe we can and need to do it
again.
Above our planet's poles, an invisible
force is at work. Hypothesized decades
before we were able to measure it
directly, this global energy force is
responsible for sculpting our atmosphere
and driving charged particles into
space. It's also why some planets end up
uninhabitable altogether. It's called
the ambiolar field and it's a force as
fundamental to our Earth as gravity or
magnetic fields. Although for the sake
of life on Earth, it's a good thing it
isn't too strong. Recent breakthroughs
from NASA's Endurance Mission have
finally allowed scientists to solve a
60-year-old mystery by measuring the
ambipolar field for the first time,
proving once and for all that our planet
has a third global energy field.
I'm Alex Mccoan and you're watching
Astramm. Join me today as we unravel the
mystery of our planet's ambipolar
electric field. A phenomenon that not
only powers the polar wind, but also has
an enormous impact on our planet's
habitability.
Earth's magnetic field depicted in this
video as onionlike layers of lines helps
to shield our atmosphere from dangerous
solar energy and damaging cosmic rays.
And the gravitational field shown here
as the white glow around our planet not
only keeps us planted on Earth's surface
and stops our atmosphere from drifting
away, but also provides valuable
information in the study of Earth's
changing climate, sea level rise, ocean
circulation, and much more. As you can
see, our magnetic and gravity fields are
critical features that help make our
planet habitable. And with the recent
publication of a 2024 paper in the
journal Nature, direct evidence has been
found for a third energy field, the
ambiolar field.
To understand this energy field, we need
to talk about plasma.
Like a solid, liquid or gas, plasma is
another state of matter which happens to
make up 99% of all visible matter in the
universe. Plasma is made of ionized
particles and is responsible for several
well-known phenomena on Earth like the
aurora borealis and lightning.
Plasma can form where atmospheric gas
density becomes low enough to support
the conditions for it and around 90 km
above Earth's surface. This plasma is
made up of very lightweight, fastm
moving particles, which get trapped
along the Earth's magnetic field lines
as they move away from the surface.
Around the majority of our planet,
plasma encounters a barrier that limits
its escape into space known as the
plasma pores. Here, plasma co-rotates
along with Earth along its closed
magnetic field lines.
Until the mid 1960s, the prevailing
model of our planet's magnetic field
theorized that all of the magnetic field
lines were closed and the plasma
remained trapped. So what changed? We
went to space.
In the 1960s, the first spacecraft
flying over our planet's north and south
poles could actually detect a supersonic
wind of charged particles or plasma
flowing out to space, including
positively charged hydrogen and oxygen
ions. This observation led scientists to
start wondering whether the Earth's
magnetic field model should have an open
rather than a closed tail.
At the time, scientists already knew
that our atmosphere lost some particles
to space due to thermal escape. This is
a type of atmospheric escape that
typically happens when the energy from
sunlight heats up particles in our
atmosphere, allowing them to reach
escape velocity and break free of our
planet's gravitational pull. Kind of
like when a pot of water boils and steam
evaporates. So, it was no surprise that
some particles would be escaping into
space. But something didn't quite add
up.
If energy from the sun were the only
cause of atmospheric escape, one would
expect the particles that were escaping
into space to be heated. However, many
in the stream were actually cold with no
signs of being heated. And yet, they
were traveling at supersonic speeds.
Scientists hypothesized that there must
be another invisible force driving this
phenomenon. And in 1968, the term polar
wind was coined to describe it, leading
to more research and theories into its
cause and effects.
The idea of a planetwide electric field
was developed to explain the polar wind.
But when this was theorized in the
1960s, it was thought that the force was
too weak to detect. And at the time,
scientists were correct. The electric
potential was so weak, it would require
very sensitive instruments to measure,
and that technology wouldn't be invented
for several more decades.
Enthusiasm to measure our planet's
ambipolar field was spurred again in
2016 after a clue came from the European
Space Ay's Venus Express mission.
One of the reasons that Earth is
hospitable for life is because of its
water. While Venus today is dry and
barren. However, billions of years ago,
evidence suggests that Venus might have
had abundant water like our own world
does now. This raises the intriguing
question, if Venus once had water, where
did it all go?
The issa's Venus Express mission offered
a potential explanation when it detected
a 10V electric potential around Venus,
at least five times larger than
expected. This marked the first
successful measurement of an electric
field on any planet, including Earth.
The electric field surrounding Venus
could pull positively charged ions like
oxygen out of the atmosphere, draining
it of the essential ingredients of
water, like a vacuum cleaner siphoning
particles out to space. Over time, this
could have played a role in draining the
planet of its once abundant water. This
prompted a question much closer to home.
Does Earth have a similar electric
field? And if so, why has our planet
managed to hold onto its water?
The electric potential measured around
Venus was around 10 V. For comparison, a
standard car battery is 12 V, but
scientists expected our planet's
electric potential to be as little as
0.3 V, similar to a button battery you
might find in a watch, and some 25 times
weaker than the electric potential on
Venus. It's this difference that may be
a key reason why our Earth has been able
to keep its water. And that's what
inspired NASA's Endurance team to
develop a new type of scientific
instrument called a photo electron
spectrometer to find Earth's weak
electric field. The instrument is
designed to measure the speed of
electrons escaping from Earth's
atmosphere as a way to reveal our
planet's electric potential.
Earlier I explained thermal escape and I
mentioned that particles are able to
escape from our atmosphere when they
reach escape velocity. That escape
velocity is a very specific predictable
speed. But this speed should be ever so
slightly slowed by Earth's electric
potential.
And so by measuring that slowing effect
at apogee or the furthest point in
Endurance's orbit from Earth, the
instrument would be able to measure the
strength of the electric potential
around our planet. Such a sensitive
instrument would need to be launched at
precisely the right location and time.
In order to ensure a chance at making
the observation successful, the Spalbad
rocket range was selected for the job.
It's the northernmost range in the world
located in Swalbad, Norway, a group of
islands in the Arctic Ocean. Here, the
NASA Endurance team would be able to
launch the instrument on a suborbital
rocket through Earth's magnetic north
pole. And on the 11th of May, 2022, the
team of international scientists did
just that.
Named after the ship that carried Ernest
Shackleton's crew in their 1914 attempt
to reach the South Pole and cross
Antarctica, the Endurance mission
launched its suborbital rocket to an
altitude of 768 km, collecting data over
518 of those kilm before splashing down
19 minutes later in the Greenland Sea.
During its flight, the instrument
measured a change of 0.55 volts in
electric potential between 250 km and
768 km. Space scientist Glen Collinsson,
the principal investigator for NASA's
Endurance mission, said even though half
a vault is almost nothing, again almost
about the strength of a watch battery,
it's just the right amount to explain
Earth's polar wind. This first ever
direct measurement of Earth's electric
field marked a pivotal moment in our
understanding of this fundamental
planetwide energy force.
The ambipolar field exists in what's
called the ionosphere, a region that
stretches across three out of five of
our atmospheric layers. Our atmosphere
is divided into five main layers. The
troposphere, also known as the lower
atmosphere, only reaches about 20 km
above Earth's surface and is where the
majority of weather occurs. Next is the
stratosphere, which extends up to about
50 km and contains most of our planet's
ozone that protects us from ultraviolet
radiation from the sun. This layer has
very little circulation and is where
commercial airlines usually fly. Above
the stratosphere is the messosphere,
extending up to about 85 km. This is
where meteors burn up near the bottom of
the mesosphere layer are thick enough to
slow them down. It's within the upper
reaches of the meosphere that the
ionosphere begins, but its influence
stretches far beyond that. Starting
around 80 km above the surface in the
meosphere, the ionosphere continues
outward through the entire thermosphere
layer from about 85 to 600 km. This is
where auroras happen and high energy
ultraviolet and x-ray radiation are
absorbed creating charged particles.
And finally, the ionosphere ends in the
lower exosphere, which begins around 600
km and continues out to about 10,000 km
from Earth's surface, where it fades
into outer space. The exosphere is where
many satellites orbit around our planet.
As you can see, the ionosphere starts
around 80 km above sea level and
stretches hundreds of kilome into space
where it overlaps with Earth's
magnetosphere, a region of space
surrounding Earth. Within this massive
region of the ionosphere is where we
find the ambiolar field, which is
theorized to begin at around 250 km.
While most of our atmosphere is composed
of nitrogen, the upper region of our
ionosphere is home to lighter elements
like oxygen, hydrogen, and helium. When
photons from the sun collide with these
elements in the upper atmosphere, they
can knock electrons loose from the
elements in a process called ionization,
leaving positively charged particles
called ions and negatively charged
electrons.
Because of the opposite charges of the
negative electrons and positive ions,
they are attracted to each other and
become tethered together by an electric
field. It's this electric field that
constitutes a major part of the ambiolar
field. The electrons within the electric
field are so light that the slightest
push could send them flying out to
space. While the ions are more than
1,800 times heavier than the electrons
and sink toward the ground due to
gravity, the subatomic tug of war works
in both directions. But the upward tug
from the energized electrons is able to
just slightly overwhelm the force of
gravity on the ions. This outward
pressure of ionospheric electrons is
what creates the ambipolar field
depicted here as the sparkling blue glow
around our planet. The upward lift
inflates our planet's ionosphere and
accelerates some ions enough to escape
from the atmosphere, creating the polar
wind along our poles magnetic field
lines. What's more, the ambipolar fields
can achieve this acceleration of plasmas
without heating them, providing an
explanation for the cold plasma
scientists have detected escaping from
the ionosphere. It's the birectional
nature of the interaction between ions
and electrons that gives the ambipolar
field its name. The Latin prefix ambi
means both and polar refers to the polar
regions where the electric fields
effects are felt the strongest.
Collinsson, the Endurance mission's
primary investigator, called the ambi
polar field an agent of chaos, stripping
particles from our atmosphere away into
space. Hydrogen ions make up the
majority of the polar wind. They are so
light the ambipolar fields upward force
of these electron ions is 10.6 6 times
stronger than the force of gravity,
leading the ions to accelerate up at
supersonic speeds and escape from our
atmosphere above the Earth's magnetic
poles. Scientists have found that our
planet loses about 3 kg of hydrogen gas
every second or 95,000
tons per year. Additionally, the Earth
also loses about 50 g of helium per
second or 1,600 tons of helium gas per
year. a smaller but still measurable
amount and a much smaller amount of
other gases like oxygen. However, not
all of this is due to polar winds. It
occurs through a combination of factors
including thermal escape and
non-therrmal escape mechanisms such as
polar wind. But don't worry, despite our
planet losing several thousand tons of
its atmosphere to space every day, we
are nowhere near running out of air. The
planet won't run out of oxygen for a
billion years. It will be another
billion years after that before our
oceans will have been depleted of most
of their hydrogen. Around 4 billion
years from now, our planet may look very
similar to how Venus looks now. All of
our water will have evaporated and the
greenhouse effect will have become
strong enough to melt rock, leaving our
planet a dry, lifeless world. Keep in
mind that modern humans have only
existed on this planet for around
300,000 years. Our species would need to
exist more than 3,300 times that length
to be around in 1 billion years.
While not really important on human time
scales, it is still interesting to think
about though. And while hydrogen ions
may be the lightest and most common type
of ion to escape in a polar wind,
heavier particles also get a boost from
the ambipolar electric field, helping to
shape our atmosphere's structure and
dynamics. How exactly? Well, now that
we've measured the ambipolar field,
scientists can delve into all the ways
the ambipolar field shapes our
atmosphere. Take oxygen ions for
example. These heavy ions weigh half as
much when they're immersed in the 0.55
volt ambipolar field. This effect
increases the ionosphere's scale height
by 271%
which means our atmosphere can remain
denser at greater heights than it would
otherwise be able to. Endurance's
discovery and measurement of the
ambipolar field also provided an
important key to understanding why Earth
has been able to hold on to much of its
water up until this point. While our
neighboring planet Venus was not able to
do the same. It's theorized that any
planet with an atmosphere may also have
an electric field. And you may recall
that earlier I said Venus's electric
potential was measured to be around 10
volts, roughly 18 times stronger than
the ambiolar field on our own planet.
While Earth does lose a constant flow of
particles to space, both through the
polar wind as well as other types of
atmospheric escape, this effect would
have likely been much more pronounced on
Venus because of its stronger electric
potential, leading to the loss of
heavier particles like the ones that
make up water. The fact that our
ambipolar field is so weak may be an
important part of why our planet has
been able to hold onto its water. We've
only just started to explore the depths
of how the ambipolar field has
influenced our planet and life on Earth.
And the Endurance scientists have said
there are already plans for additional
measurements of our planet's ambipolar
field in the future. Like its
predecessor, the new rocket will also
carry the legacy of a long past Arctic
explorer named after the Resolute, a
ship that set off to explore the Arctic
in 1850.
And now that we've finally been able to
confirm and measure the ambipolar field
strength and with a follow-up mission
already planned to take more
measurements, scientists can start
asking some of the bigger and more
exciting questions like what it means
for Earth's complex atmospheric dynamics
and how it helps to govern planetary
evolution. And doesn't the potential
insights we stand to gain from this
research feel electric?
NASA's Mars Reconnaissance Orbiter has
been imaging the surface of Mars for
over 10 years now with its powerful
high-rise camera.
10 years of taking photos every day
means that its catalog is huge and we
can pick out pretty much any part of
Mars that we want to have a closer look
at.
Today, I thought it would be really
interesting to investigate the sandjunes
on Mars and see how they compare to the
wonderful sandjunes we have on Earth.
You may have already seen imagery of the
Sahara Desert with dunes hundreds of
meters tall or the Namib Desert with
rolling sandunes as far as the eye can
see.
Did you know though that there are five
different types of sandjunes and that
Mars has a type of June Earth doesn't
have? And also, what are the biggest
Junes on Mars?
The most common type of sandjune on
Earth is the cresant or the Bhan
sandjune. While not always as
distinctive as these dunes in this
image, they are plentiful and found in
most sand deserts.
They are defined by this kind of cresant
shape with arms and they are usually
wider than they are long like you can
see here. They form like this because in
these places there is only one dominant
wind direction. They have a shallow
slope on one side that faces the wind
and a slip face on the other side.
They are a type of transverse June. As
they move gradually over time as the
wind blows, whipping sand from the
front, over the top, and down the slip
face.
When many of them merge, they can create
an almost wave of sand, smooth on the
side, face in the wind with a slip face
away from the wind, moving gradually
over time with the wind's direction.
They are also in plentiful supply on
Mars. All of the ones I'm about to show
you can be found at the base of various
large craters. Going to this old crater
near Mars's equator. Bhan dunes can be
seen lumped together somewhat here in
this plane. This happens when there is a
plentiful amount of sand and the dunes
merge together into a big lumpy
transverse June.
But individual dunes are really evident
a bit higher up where the sand is
contrasted against the bedrock. Here are
some more found in Arch Angle Ski
Crater.
When there is a smaller amount of sand,
the dunes tend to stay separate, which
looks really peculiar from above.
These dunes do move, although very
slowly. Here's a couple of examples of
dunes on Mars, moving slowly over the
course of 2 to 3 years. Scientists
originally thought that sandjunes would
stay pretty motionless on Mars as
sandjunes require wind to move them and
Mars only has about 1% of the
atmospheric pressure at the surface
compared to Earth whose winds can easily
move sand.
We knew the wind on Mars could pick up
tiny dust particles, but it would
require extremely strong winds to move
sand.
This could be helped though by the fact
that sand on Mars is not exactly the
same as Earth's sand. In my Opportunity
video, I mentioned that the sand
particles Opportunity analyzed were far
smaller than what we're used to on
Earth, which may aid the movement of
these dunes.
But what happens if the wind is
birectional?
Going back to Earth, a beautiful type of
June which can easily be seen all the
way from the International Space Station
is the longitudinal or seifrabic
word for sword which describes these
dunes nicely as they are long and
narrow.
These linear dunes can be hundreds of
kilome long and are often found in
parallel sets separated by gravel or
rocky corridors.
These occur where wind directions can
flip over, meaning that these ridges
have a slip face on either side of the
dune, making them appear quite sharp.
Seafunes also appear on Mars. And in my
opinion, the most beautiful example of
it can be found here.
again found at the bottom of a crater.
These tunes look remarkably similar to
each other, including this dusty band
found on each one.
Although we're not totally sure how they
form, one leading theory is that they
are the result of wind directions
changing around Barkan Junes.
In this image, some bark and junes seem
to be mid-process of forming into seaf
dunes. It's a really pretty image that
seemingly tells a story. To our right
here, we have a measer being eroded,
feeding sand into the valley below.
Then you have these beautiful examples
of barkan dunes which show the
stepbystep process of becoming seafunes.
Another spectacular example of this a
bit further into the process can be
found here.
The contrasts of the different materials
in the image are stunning.
And the dark sections are the sandjunes
merging together.
The third type of June is the dome June.
Typically, these are not very big on
Earth, usually only a few feet high.
They have no slip face. They are smooth
all over, hence the name. They are quite
rare and usually found in and around
other types of dunes.
And yes, these are also found on Mars.
Here's a field full of domes, a few of
which can be seen starting to cross over
into Barkanjunes.
And in this impressive expanse of dunes,
and I really do mean an expanse, as
these dunes continue on way beyond this
image, you have wobbly lines of dunes
with domes on the end of them. These
domes seem to be much bigger here than
they are on Earth. The domes here, tens
of meters across.
This field is indicative of a change in
wind direction as the lines are nowhere
near as straight as in some of these
previous images.
The fourth type of June is a parabolic
June, which is the opposite of a baran
June, meaning the slip face is on the
other side compared to a Barcan June.
These occur near coastal regions and
form the way they do because something
often vegetation anchors the arms of the
June in place. Lack of vegetation on
Mars means it's a bit tricky to find
parabolic dunes.
The closest thing I found is this
beautiful image. A dune wrapped around a
large mound in the middle.
The June is clearly moving from left to
right in this image. And you can even
see the shadow of the slip face just by
here on this side.
The existence of this June is heavily
influenced by the size and shape of this
mound funneling wind along its walls.
The fifth and last type of June is the
biggest type, the star June.
This is a June where wind direction
changes frequently, meaning the dunes in
this region have three or more arms and
are often stationary, just building up
over time.
This impressive image is the Sahara
Desert as seen from the ISS, and it is
full of star dunes.
The scale of these dunes truly is
impressive. Zooming in, you'll realize
that these dots are people.
And of course, we have starjunes on
Mars.
Some are small, a collection of dunes
merged together,
but others are massive, like these found
in Russell Crater,
which reach far beyond this image. As
this image is found nearer the poles,
carbon dioxide ice can form on these
dunes. During the Martian spring, the
carbon dioxide sublimates, which
dislodges loose material, leaving these
streaks.
Moving to another image, again near
Mars's pole,
we find one of the most beautiful images
of Mars I have ever seen. This image was
taken just as the sun was either rising
or setting, meaning a lot of the image
is shadows cast by Junes.
I love this as it provides a sense of
depth to the image. These again are big
star dunes with their individual arms
reaching out for kilome.
There's one last thing I want to talk
about the dunes of Mars. Have you ever
been to the beach and seen sand ripples
like these? These are actually a type of
transverse dune forming perpendicular to
the direction of the water waves as they
flow over the sand.
Much like larger scale transverse dunes
caused by the wind.
Mars has these ripples too, but they are
much much bigger than what you would
find on Earth with a meter or two
between the ripples. This size makes it
difficult to see from space. But luckily
we have another rover on hand. Curiosity
seen here in this image
to take this remarkable photo of them.
Scientists didn't even know this type of
June existed. And it is a fitting
reminder that although Mars may appear
quite familiar to us, it is still a
world full of secrets and unexplored
facts. And there is still so much we can
learn from it.
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